A number of points of contention are evident during the planning and execution phases of the assault on Peleliu. First, and probably foremost, was the decision to launch the attack at all. Beyond this issue is the actual operational and tactical execution of the attack itself, especially in terms of leadership and organizational preparedness.

At the core of the strategic justification for the attack was MacArthur's insistence that his right flank must be protected, and that seizing the Palaus was the means by which this should be accomplished. Nimitz, for his part, had promised MacArthur the support he might need to return to the Philippines, and agreed with the general's opinion on the Palaus. Without further information, little intelligence could be produced to dispute this assessment; after all, the Palaus did present a gap between the two American axes of advance in the Pacific, and could well serve as a strategic 'shoe horn' the Japanese might use to threaten further moves by either Nimitz or MacArthur.

Admiral William Halsey, commander of the 3rd Fleet, however, reported in late August and early September that enemy resistance in the area of MacArthur's invasion was far less than expected. To this end he recommended, on 12 September, that the landings in the Palaus be canceled entirely and MacArthur's invasion of Leyte be moved up to October.(20) Those forces earmarked for the Palaus – and already at sea – should be used to supplement landings in the Philippines. Although Nimitz and MacArthur accepted Halsey's idea about moving the date for Leyte, they opted to go ahead with the Palau invasions anyway; Nimitz cited the fact that forces were already at sea and it would be too difficult to recall them. Additionally, he argued that Halsey's idea of using carrier and surface forces to isolate the Palaus would be wasteful. Although the absence of such ships might have been felt in later actions, especially the Battle of Leyte Gulf, in point of fact one of Halsey's carriers was not present for that engagement. Still, this is a view afforded only by hindsight, and therefore should not be considered in deciding the overall wisdom of the entire operation.

From the American point of view in summer 1944, and based on available intelligence, the Palaus did represent a threat to further operations. Their proximity to the Philippines and their location between the American axes of advance, coupled with the possibility of their reinforcement directly from Japan, made them a necessary target. Although captured documents and interrogations after the war concluded that the Japanese had no real plan or intention of using the Palaus as such, from an American perspective the threat did exist, and tying down vital surface forces in order to isolate and suppress the islands was not a decisive option; only taking the islands themselves would eliminate the threat completely.

The first step toward seizing Peleliu was the massive pre-invasion naval and air bombardment, and it was executed with the typical noise, smoke, and overestimation of its lethality. Although ignorance of Peleliu's rough terrain and the enemy's skilled use of it precluded the Americans from accurately estimating the effects of the fires, the navy had consistently shown too much confidence in their effectiveness. They had done so in many previous battles, much to the consternation of landing forces. Massive bombardments, although showy, loud, and surely frightening to enemy forces, had yet to reduce an island as completely as the navy asserted they could; why this assertion was again made at Peleliu is beyond understanding. The most recent operations on Guam had demonstrated that a short, however intense, bombardment, did not yield the same results as did a longer one; Peleliu experienced only 3 days of fires before D-Day.(21)

Strategy and preparatory fires aside, it was, the marines' conduct in the taking of the islands where the most critical commentary can and should be aimed. Before going into detail about this, however, it is important to dispel one possible area of fault: aerial photography. Although it was obvious to all those on Peleliu as of the morning of D-Day that the island was not flat and level, as intelligence analysts had insisted, the dense vegetation made impossible any other conclusion but this. The island did appear as had so many others throughout the Pacific: flat along the shores, and slightly hilly inland, with the majority of cover and concealment provided by flora, rather than terrain. There was little that could have been done to avoid this false conclusion about Peleliu, short of conducting extensive reconnaissance missions on the island itself, which was obviously out of the question. Thus, although the marines did face an island that appeared little as it had been described, there was equally little that could have been done to avoid this error. Mistakes are made in war; this was one of the unavoidable ones.

And so finally, it is the conduct of the marines themselves, specifically their leadership, that one must take to task. MG Rupertus was undoubtedly a tough, brave man. He had served ably in Guadalcanal and had been decorated for his leadership there. He had the utmost confidence in his men, their equipment, and his plan. American amphibious doctrine had been working across the Pacific with stunning results over the previous year, and Peleliu would be yet another validation of these methods. In these lies the greatest failing of Rupertus, and the greatest mistake by the marines: overconfidence.

Rupertus continually stated throughout the planning stages that the fight would be intense, but short. It would be a quintessential storm landing, with hard fighting on the beaches and immediately inland, but of short duration once the Japanese lines were pierced. He spoke of 'open season' on the Japanese once they began their inevitable banzai charges, and demanded that "somebody bring me the Jap commander's dress sword."(22) This was arrogance and overconfidence of the highest order, considering stiff enemy resistance continuing on Guam that summer, and the haphazard manner in which 1st MarDiv had trained and loaded for Peleliu. Morale on the part of troops and a commander's confidence are critical to victory, but such specific, bold claims on the part of a commander are irresponsible. Throughout the battle Rupertus, seemingly oblivious to the casualties his division was taking, insisted that the end was in sight, and that outside help was unnecessary. It took an order from his corps commander to get him to remove Puller's 1st Marines from the line, to be replaced by an army unit; Rupertus had repeatedly expressed his lack of confidence in the untried 81st ID, its commander, and the army in general. Apparently, it was a far better decision to sacrifice his own troops rather than take a chance on the army; inter-service rivalry is fine for enlisted men, but at the general officer level it is childish and counterproductive.

In addition to his unwillingness to accept help, Rupertus had planned an invasion for which he held only two battalions as his divisional reserve, with nothing else to back him up should the need arise. Apparently it was inconceivable to him that a situation in which his marines would need help could develop. Consequently, the 81st ID, whose attacks on Anguar and Ulithi were held up pending favorable progress on Peleliu, were launched. This, despite the fact that by D+2, the day Rupertus informed III Amphibious Corps that the 81st was not needed, 1st MarDiv was completely bogged down and suffering horrendous casualties. American intelligence knew that the garrisons on Anguar and Ulithi were smaller than the one on Peleliu, and this was precisely why the attacks on these islands were held off: so that the 81st could provide 1st MarDiv with support if needed first on Peleliu. Rupertus, stubborn to the end, had to be ordered to accept the army's assistance, and even then continued to insist that his marines would take the island shortly. Intermittent problems with water and food supplies,(23) along with stiffening Japanese resistance, and the high temperatures coupled with Rupertus' arrogant stubbornness probably resulted in more deaths than were necessary.

In the end, Peleliu itself provided very little in the way of support for further American operations, although knowledge of and experience against Japanese fukakku tactics were valuable, and would help the Americans deal with similar methods on Iwo Jima and Okinawa. The airfield at tiny Anguar proved far more useful, and the fleet anchorage at Ulithi was used extensively until the end of the war. Still, these latter truths are provided only by hindsight, and should not be used as evidence to invalidate the decisions that led to the attack on Peleliu. What should be considered, then, is how the attack itself was prosecuted, and how the same results, however useful or not, could have been reached with fewer casualties. MG Rupertus, for his overconfidence and arrogance in not planning for any real contingencies or considering the need for assistance, shoulders the lion's share of this responsibility. In the face of empirical battlefield evidence, Rupertus expected too much from his men, and refused ready assistance when offered. Although the official Marine Corps history of the battle states that it validated established amphibious doctrine, that had really already been done throughout the Central Pacific campaign, and needed little more evidence to prove its value. Peleliu exists as a costly battle, one that hindsight encourages us to declare as pointless. Its legitimacy and value was established and supported by the intelligence of the time; the bravery of the American servicemen who fought there is beyond question; therefore only the skill of its execution should be disputed.